Process of oxidizing orthonitrotoluene.



; NITED STATES PATENT OFFICE.

MAX MANDT AND ROBERT HOLDMANN, or LUDWIGSHAFEN-ON-THE-RHINE, GERMANY,ASSIGNORS TO THE BADISOHE ANILIN AND SODA FABRIK, or

SAME PLACE.

PROCESS OF OXIDIZING ORTHONlTROTOLUENiE'.

SPECIFICATION forming part Of Letters Patent N0. 650,332, dated May 22,1906.

Application filed February 6, 1900. Serial No. 4,267. (No specimens? Toall whom it may concern:

Be it known that we, MAX MANDT, doctor of philosophy, and ROBERTHOLDMANN, subjects of the King of Bavaria, residing atLudwigshafemon-the-Rhine, in the Kingdom of Bavaria and Empire ofGermany, have invented new and useful Improvements in Proc esses for theOxidation of Orthonitrotoluene, of which the following is aspecification.

It is known that certain methyl derivatives of benzene can be oxidizedin the sidechain by means of manganese peroxid in acid solution and soconverted into corresponding aldehyde compounds. (See the specificationI 5 of the German Patent No. 101,221.) According to the saidspecification the formation of carboxylic acid is almost entirelyprevented when a large excess of the methyl derivative is present duringthe reaction. Further, although tolnene,xylene,and the like are readilyoxidized the oxidation of ortho-nitro-toluene proceeds with ditficultyunder the conditions therein described. Thus if ortho-nitro-toluene betreated according to the conditions 2 5 described in the Examples 1 and2 of the said specification-that is to say, at a temperature of 40 orcentigrade, respec- Lively-only traces of ortho-nitro-benzaldehyde areformed, if any. We have found 0 that under suitable conditions,hereinafter set forth, the oxidation of ortho-nitro-toluene in the sidechain can be very readily effected with the aid of manganese peroxid andsulfuric acid. If the conditions be suitably chosen,ortho-nitro-benzaldehyde or the corresponding carboxylic acid can beobtained as desired, even though an excess of orthonit-ro-toluene bepresent. The conditions to be observed are that the temperature must beessentially higher-over 100 centigradeand the concentration of thesulfuric acid must be varied according to the object it is desired toeifect. If dilute acid be used, ortho-nitro-benzaldehyde is the productobtained, while with stronger acids ortho-nitrobenzoic acid is theprincipal product. It is recommended that the treatment be effected inclosed vessels, so that the mass can be heated above the boiling-pointunder ordinary pressure and the desired temperature, of reaction beobtained. When working with stronger acids, an arrangement should bemade to neutralize the effect of the water formed, diluting the sulfuricacidnamely, by adding during the reaction more concen 5 5 trated acid.The vessel in which the reaction is efiected is preferably lined withlead and furnished with a stirrer and a manometer, and it should beprovided with a valve which, while maintaining the desired pressure,permits the escape of the reaction gases if the pressure rises higherthan'is desirable.

The following examples will serve to illustrate the manner in whichour-invention can be carried into practical eifect, (the parts are byweight Example 1.Producti0n of ortho-nitro-benzaldehyde as mainproduct.-Mix together one hundred (100) parts of ortho-nitro-toluone,one thousand (1,000) parts of dilute sulfuric acid, (containing fromthirty-five to forty-eight per cent. H 80 and two hundred (200) parts offinely-powdered manganese peroxid. Introduce the mixture into a vesselcapable of withstanding pressure, ar- 75 ranged as hereinbefore stated,and heat for about two or three hours at a temperature of about 140 to165 centigrade. Adjust the valve of the vessel so that a pressure ofabout ten atmospheres is not exceeded. When the reaction is finished,allow the mixture to stand, so that any manganese peroxid in suspensionmay settle. Oollect the oil which floats upon the acid liquid and washit with water and with a solution of carbonate of 85 soda. Thistreatment-withdraws any orthonitro-benzoic acid that may have beenformed as a by-product. Shake the oil after this treatment with sodiumbisulfite in the cold. The ortho-nitro-benzaldehyde dissolves and can beseparated and obtained in a nearlypure condition by the addition ofalkalies.

Example QPr0ducti0n of ortho-mtro-benzotc acid as main product.Prepare amixture of the same ingredients as those set forth 5 in Example 1,except that stronger acid is to be takennamely,acid containing fromsixtytwo to seventy-eight per cent. of H 80 Heat the mixture in thepressure vessels prefer ably only to a temperature of 135 to 145centigrade. Adjust the safety-valve so that the gas formed during thereaction can escape if the pressure rises too high. When working in thisway, on treating the oil that results in the manner described in Example1 a'large quantity of ortho-nitro-benzoi'c acid is obtained, while asmall quantity of orthonitro-benzaldehyde is mixed with it as abyproduct. It is not absolutely necessary to work in closed vesselsunder pressure. Similar results can be obtained when working at ordinarypressure, using a vessel provided with an inverted condenser; but whenwork ment with dilute sulfuric. acid containing about thirty-five toforty-eight per cent. H 80 and manganese peroxid at a temperature of 140to 165 centigrade at a pressure not exceeding ten atmospheressubstantially asdescribed. 7

3. "The process of making ortho-nitro-benz'oi'c acid and ortho nitroben'zaldehyde by the oxidation of ortho-nitro-toluene bytreatment withdilute sulfuric acid containing about sixtytwo to seventy eight percent. H SO and manganese peroxid at a temperature of about 135 to 145centigrade substantially as described.

4. The process of making an ortho-nitro derivativewhich consists in theoxidation of ortho-nitro-toluene in the side chain by treatment withsulfuric acid and manganese peroxid at a temperature above 100centigrade,

substantially as described.

In testimony whereof we have hereunto set our hands in the presence oftwo subscribing witnesses.

MAX MANDT. ROBERT HOLDMANN.

Witnesses:

ERNEST E. EHRHARDT, JACOB ADRIAN.

